Here's what I've found about the musical (via link). I'll supply the lyrics in a subsequent post, but thought it may be beneficial to include some additional information I've found.

Songs:
(Original production - in alphabetical order)

Angelus
The Cricket On the Hearth
Every Lover Must Meet His Fate
For Every Lover
Game Of Love
Hail, Franz of Zilinia
I Don't Know How I Do But I Do
I Might Be Your Once-in-a-While
In the Convent They Never Taught Me That
Iron, Iron, Iron
Mother Goose
On Parade
Pretty As A Picture
Smiles
Sweethearts (If You Ask Where Love Is Found)
There Is Magic In A Smile
Waiting For the Bride

Based on the lines supplied, I'd have to guess it's the bolded song, I Don't Know How I Do But I Do.